Canon LBP7210Cdn Manual page 323

(1) Select the combined job.
(2) Select [Print] from the [File] menu.
The printer starts printing.
NOTE
Combined jobs are not saved.
After the combined job is printed, the job is deleted from Canon PageComposer.
The job is also deleted if Canon PageComposer is closed without printing the job.
For more details on Canon PageComposer
See Help for Canon PageComposer.
Help is displayed by clicking [Help] in the [Help] menu.